Venus Conjunctions, the Pleiades & the Sheaf

Keith M. Hunter

Marking the End of a Sheaf: Venus vs. The Pleiades

With all that has so far been said of the precise mechanics of the
Sheaf cycle, and of the fact that the Maya and Aztecs both held
ceremonies to mark the completion of the Sheaf, one could be forgiven
for thinking that 2.6 days prior to the end of every 52 calendar year
period (18977.4 days), a most accurate conjunction would be in evidence
between Venus and the Earth; for indeed, is not the purpose of the Mayan
Calendar as with any calendar, to track and harmonise real astronomical
cycles?

Well, apparently, according to historical records, the Aztecs and
Maya, rather than set the end of each sheaf to coincide with an actual
Earth-Venus conjunction, set it to coincide with an altogether
completely different celestial event: a conjunction of the Earth and the
Pleiades.

Pleiades-Earth Alignment

A closely packed group of seven stars, the Pleiades are sometimes referred to as the Seven Sisters. But to such as the Aztecs, they were known as the Cabrillas.
According to accounts provided by the early Spanish explorers of the
16th century, every 52 years the ceremony to mark the end of a sheaf
period coincided with a precise observation of the Pleiades star group
at midnight, when it appeared exactly upon the meridian. Now to be
clear, in terms of a night-time observation, there is only one
particular day of the year when such an event will happen; when one is
able to observe the star cluster at the precise time of midnight, and at
such a time when the stars themselves are located on the meridian line.
At the precise moment though when this does happen, there is an active
conjunction in evidence between the Pleiades, the Earth, and the sun. As
indeed, at such a moment, exactly 180 degrees around the other side of
the Earth, the Sun itself is at the ‘12 noon position’, and thus
directly ‘behind’ the Earth and so lined up with the Pleiades.

In view of the above, it should be readily apparent then that
there will be a notable discrepancy between the time interval of 32.5
Earth-Venus conjunctions (18977.4 days) and the time interval between
two Earth-Pleiades conjunctions at 52 years apart. Indeed, the reason
for this is that each of the two conjunction events involve, or rather
rest upon, a different type of Earth year. In the case of the former,
one is speaking of 52 calendar years, each of 365 days in length. In
terms of the latter, 52 sidereal years, each of 365.256363 days. That
this is so is due to the fact that the Pleiades, as a background star
group, is susceptible to precession. One may note the difference between
the two time intervals as follows:

Earth-Pleiades Cycle: 52 x 365.256363 = 18993.33088 days

Earth-Venus Cycle: (52 x 365) – 2.6 = 18977.4 days

18993.33088 – 18977.4 = 15.930876 days

In careful consideration of the above, there is nothing in and of
itself that would suggest that a time interval of 52 sidereal years is
of significance, purely from an examination of the basic time cycles
that compose the Sheaf i.e. 365 and 260 days. Indeed, it is not clear at
all how one could derive a time interval of 18993.33088 days from
18977.4 days, employing any sort of basic correction measure, with
elegance or precision.

On the face of it therefore it would seem as if the two noted 52
year cycles are very much separate in terms of their actual physical
duration, and that the Pleiades conjunction cycle is only loosely based
upon the Sheaf. And yet, somehow over time, has taken precedence over it
to become the celestial event to mark the end of such a period.

But why is this?

Just what made the 52 year Earth-Pleiades conjunction event so important to the Maya and the Aztecs?

A Day of Disaster

The key reason why an Earth-Pleiades conjunction was held to be of
such importance to the Maya and the Aztecs, is that it was taken to be a
signal that could potentially mark ‘the end of the world’. Indeed, the
Central American Indians were of the firm belief, in accordance with
their prophecies and oracles, from an era almost lost to history, that
at some future date, the very movement of the heavens itself would
cease, and that this would occur at the time of an Earth-Pleiades
conjunction following the completion of a Sheaf cycle. Of course,
exactly which future Sheaf would herald this day of disaster was not
known, and this indeed had an important bearing upon the ceremonies of
the Aztecs in particular. This is because at the very moment of the
Pleiades-Earth conjunction at the end of a sheaf period, a human
sacrifice was made by cutting out the heart of a captive warrior, with
the belief that this very act would ‘keep the world turning’ and prevent
the heavens from cessation of motion.

Ritual Sacrifice

That the Aztecs and Maya conducted human sacrifice is rooted in
an ancient myth concerning the very creation of the world, and of its
setting into motion. An account of the myth essentially held that in a
far off age when the world was first formed, a council of gods was
assembled about a sacred fire. And that these gods sacrificed themselves
by throwing themselves into the flames, which led to the sun making its
first appearance on the horizon and being set into motion. Over the
course of time following the successive transmission of this ancient
myth, the Aztecs and the Maya began to believe at some point that such
sacrifices were periodically necessary in order to actually maintain
celestial motion. And to this end, they sought to recreate the original
sacrifice of the gods with a ritual ceremony of their own.

Lasting for a total of five days during the end of each sheaf
period, the whole of the populace in the surrounding villages of the
Mayan-Aztec Empire would partake in a ritual extinguishing of all of the
fires throughout the community. They would then take to the hills at
the culmination of the ceremony at midnight, when the critical
observation of the Earth conjuncting the Pleiades was to occur. At the
moment of the alignment the Indian priests would stab the warrior to
death and cut out his still beating heart. They would then start a new
fire within his chest cavity and bathe his heart within the flames. If
at the precise moment of the sacrifice the Pleiades failed to cross over
the meridian at midnight then the Indians knew that the world would end
as the heavens had ceased to move, and their sacrifice had not been
sufficient. If however the Pleiades continued on its course then this
was taken to be a sign that the sacrifice had been sufficient and that
the world would last at the very least for another 52 years, at which
time yet another sacrifice would of course have to be made.